采用sys-gmm.通常会报告两个sargan值，检验结论在有些情况下是相反的。如：

Sargan test of overid. restrictions: chi2(24)   =  67.47  Prob > chi2 =  0.000
  (Not robust, but not weakened by many instruments.)
Hansen test of overid. restrictions: chi2(24)   =  22.74  Prob > chi2 =  0.535
  (Robust, but can be weakened by many instruments.)
如何进行最终判断？

谢谢！